The present invention relates to telecommunication techniques. More particularly, the present invention provides a 56 Gbps PAM4 driver for silicon photonics based Mach-Zehnder Modulator for high-rate optical data transmission, though other applications are possible.
Over the last few decades, the use of communication networks has exploded. In the early days Internet, popular applications were limited to emails, bulletin board, and mostly informational and text-based web page surfing, and the amount of data transferred was usually small. Today, Internet and mobile applications demand a huge amount of bandwidth for transferring photo, video, music, and other multimedia files. For example, a social networks like Facebook, process more than 500 TB of data daily. With such high demands on data transfer, existing data communication systems need to be improved to address these needs.
Progress in computer technology (and the continuation of Moore's Law) is becoming increasingly dependent on faster data transfer between and within microchips. Optical interconnects may provide a way forward, and silicon photonics may prove particularly useful, once integrated on the standard silicon chips. DWDM optical transmission over existing single-mode fiber with data-rates of 32-Gbit/s or higher is a target of the next generation of fiber-optic communication networks. Everything is okay up to 10 Gbits/s, but beyond that, distortion and dispersion take their toll. Many approaches are proposed on modulation methods for transmitting two or more bits per symbol so that higher communication rates can be achieved. Mach-Zehnder (MZ) modulators can handle the higher data rates but require a driver that is differential with a large output voltage swing, sufficiently high maximum oscillation frequency, and minimized parasitics. Therefore, improved driver design and implementations for 56 Gbps data-rate are desired.